fix: remove unwrap which is causing panics closes #1073

crates/aiken/src/cmd/uplc/decode.rs

@@ -1,4 +1,4 @@
-use miette::IntoDiagnostic;
+use miette::{Context, IntoDiagnostic};
 use std::{path::PathBuf, println};
 use uplc::ast::{DeBruijn, Name, NamedDeBruijn, Program};
 
@@ -39,16 +39,14 @@ pub fn exec(
         std::fs::read(&input).into_diagnostic()?
     };
 
-    let pretty_uplc = match from {
+    let program: Program<Name> = match from {
         Format::Name => {
-            let program: Program<Name> = if cbor {
+            if cbor {
                 let mut flat_buffer = Vec::new();
                 Program::from_cbor(&bytes, &mut flat_buffer).into_diagnostic()?
             } else {
                 Program::from_flat(&bytes).into_diagnostic()?
-            };
-
-            program.to_pretty()
+            }
         }
         Format::NamedDebruijn => {
             let program: Program<NamedDeBruijn> = if cbor {
@@ -58,9 +56,10 @@ pub fn exec(
                 Program::from_flat(&bytes).into_diagnostic()?
             };
 
-            let program: Program<Name> = program.try_into().unwrap();
-
-            program.to_pretty()
+            program
+                .try_into()
+                .into_diagnostic()
+                .context("failed to decode, maybe try `--cbor`")?
         }
         Format::Debruijn => {
             let program: Program<DeBruijn> = if cbor {
@@ -70,13 +69,14 @@ pub fn exec(
                 Program::from_flat(&bytes).into_diagnostic()?
             };
 
-            let program: Program<Name> = program.try_into().unwrap();
-
-            program.to_pretty()
+            program
+                .try_into()
+                .into_diagnostic()
+                .context("failed to decode, maybe try `--cbor`")?
         }
     };
 
-    println!("{pretty_uplc}");
+    println!("{}", program.to_pretty());
 
     Ok(())
 }

crates/uplc/src/debruijn.rs

@@ -461,7 +461,12 @@ impl Converter {
 
     fn get_unique(&mut self, index: &DeBruijn) -> Result<Unique, Error> {
         for scope in self.levels.iter().rev() {
-            let index = Level(self.current_level.0 - index.inner());
+            let index = Level(
+                self.current_level
+                    .0
+                    .checked_sub(index.inner())
+                    .ok_or(Error::FreeIndex(*index))?,
+            );
 
             if let Some(unique) = scope.get_right(&index) {
                 return Ok(*unique);